How much work is done by the centripetal force on an object moving in uniform circular motion?

$A$ particle $P$ is moving in a circle of radius $a$ with a uniform speed $v$. $C$ is the centre of the circle and $AB$ is a diameter. When passing through $B$,the angular velocity of $P$ about $A$ and $C$ are in the ratio:

If a body is moving in a circle of radius $r$ with a constant speed $v$,its angular velocity is:

If the speed $(v)$ and radius $(r)$ of a particle performing uniform circular motion are both doubled,find its new centripetal acceleration.

$A$ particle $P$ is moving in a circle of radius $a$ with a uniform speed $u$. $C$ is the centre of the circle and $AB$ is the diameter. The angular velocity of $P$ about $A$ and $C$ are in the ratio:

An athlete runs along a circular track of diameter $80 \ m$. The distance travelled and the magnitude of displacement of the athlete when he covers $3/4$th of the circle is (in $m$):